Reports of the naturally-aspirated engine's demise have been greatly exaggerated. Okay, so they haven’t actually; most car makers, from Audi to Mercedes are downsizing and turbocharging their power units - but Mazda apparently, isn’t...

While you can find a 1.0-litre turbo’d motor rattling around under the cavernous nose of the Ford Mondeo, Mazda has seen fit to install a turbo-less 2.5-litre in its updated 6 saloon and estate. Alongside this commended dedication to the turbo-less cause, the company has also tweaked the styling of its big saloon, with new grilles, revised LED headlights plus new alloys and slightly different bumpers and boot lid.

Despite its substantial underbonnet real estate, this range-topping 6 only manages to squeeze out 191bhp – similar to the power Ford extracts from its 1.5-litre unit. Worse, the Mazda can only muster 190lb ft of torque – barely more than the boosted 1.4-litre engine churns out in the VW Passat. What’s all this then?

Further muddying the purpose of this most powerful 6 is the standard-fit self-shifter – a conventional automatic rather than the rapid-shifting dual-clutch ‘boxes of many rivals.

So, what’s all this then? Is the range-topping 6 a super-spec cruiser or a sporty, high-revving machine that eggs you on at every opportunity?

Further muddying the purpose of this most powerful 6 is the standard-fit self-shifter – a conventional automatic rather than the rapid-shifting dual-clutch ‘boxes of many rivals.

So is the range-topping 6 a super-spec cruiser or a sporty, high-revving machine that eggs you on at every opportunity?

Startling snarl, performance less startling

Fire up the 2.5-litre motor and flatten the throttle and you’re greeted with an aggressive subterranean growl from under the bonnet as the revs rise.

Modern petrol engines are so quiet that they’re practically inaudible in most saloons. Mazda has gone for a different approach with the 6, however. Dawdle around town and there’s not much engine noise, but work the car harder and the engine greets you with a hard-edged note.

This firmly puts the 6 into the driver’s car camp, with the noise appearing to be actual engine sound, rather than a synthesised tune piped through the bulkhead or filtered through the speakers.

Unless you make full use of the throttle travel, though, this isn’t a quick car. Gentle throttle inputs are fine around town, but this is an engine you need to keep in the top half of the rev range to make swift progress.

Since it only comes with a six-speed auto, you’ll want to use more pressure than you’re used to, to encourage the gearbox to shift down – or manually take control with the wheel-mounted paddles. Do this and the engine feels satisfyingly responsive. Yes, you may have to work it hard to even keep up with a turbocharged 1.4-litre Passat, but this is by far the more engaging car to drive.

As with that Passat, the new Mazda engine features cylinder deactivation – with half the cylinders shutting down when under little load – in this case operating between 25mph and 50mph to boost economy. Unlike the VW, there’s nothing to show when this takes place, and we found it totally imperceptible on our drive.

Fast-shifting auto ‘box

Another factor that separates the Japanese car from its German rival is that it has a conventional six-speed automatic gearbox rather than a twin-clutch unit. In theory that makes the Passat the more responsive, more economical option. However, in reality, it’s how the 6’s engine pairs with the ‘box that sets them apart.

While the Passat and most modern turbo’d saloons have a glut of torque at low revs, you have to wind the 6 up to 4,000rpm for maximum muscle – and even then the 2.5-litre Mazda barely offers more pulling power than the 1.4-litre VW. This takes a bit of getting used to, if you regularly drive modern diesels or boosted petrols.

Become a bit firmer with your right foot or select the gearbox’s Sport mode and the engine feels much more responsive. If you prefer torque-rich motors, Mazda has also updated its more powerful 2.2-litre diesel engine, raising power from 173bhp to 181bhp.

More importantly, torque stands at a gargantuan 328lb ft – enough to seriously trouble the front tyres and probably make the diesel a far more effortless drive with the automatic gearbox, though you can get it with a manual, too.

Weightier steering and agile handling

Aside from the new engine, the 2.5-litre 6’s steering feels much weightier than the next most powerful petrol version – the 163bhp 2.0-litre. It’s still not overly heavy, but feels a bit more suited to a car of this size, providing a good sense of connection with the front tyres.

The suspension has also been tweaked and offers a firm but smooth ride, very effectively cushioning you from good road surfaces and quickly settling after bigger bumps. It remains agile around corners, too, with the steering, suspension, brakes and throttle all responding immediately to driver inputs.

Yes it’s a large saloon, but the 6 flows very nicely around corners, even if you up the speed. No it’s not sharp like an M3, but it’s agile and feels light on its feet, only feeling its size if you drive it like you stole it.

Plusher cabin, increased tech

Mazda hasn’t just upped the power, range-topping GT Sport Nav+ trim – the only one available with the 2.5 – includes a tonne of standard kit.

Mazda has also sharpened up the look of the cabin with plusher materials, a redesigned dash and more comfortable seats. The difference may be subtle, but we found the updated model very comfy and a notable step above previous 6s – especially with the optional light leather trim across the seats, doors and dash.

Adding to the more luxurious feel is greater refinement, courtesy of thicker noise insulation pads stuffed in and around the cabin. No, you won’t mistake the 6 for an Audi, but you get a lot of equipment and a good feeling of quality considering the competitive cash prices and very appealing PCP finance offers available from Mazda.

What on earth is G-Vectoring Control?

This new software fractionally cuts the amount of torque sent to the front wheels when cornering. This transfers a tiny amount more weight onto the front end, boosting traction, cornering response and accuracy. The aim is to deliver a smoother, more easy-going drive.

Mazda states that this is the only system to take steering inputs into account in how and when it reduces power – enabling smoother transitions between accelerating, braking and turning. Consequently, the company claims, the car’s balance is also improved.

Meanwhile, fewer steering corrections should be needed on straight roads, meaning reduced driver fatigue and delivering greater comfort for passengers. This kit is standard across the updated 6 range and can’t be switched off, though you’re unlikely to ever notice it working.

And what are the diesels like?

The new noise-reducing tech in the diesel engine, which works to reduce clatter, contributes to an even quieter drive – and, as before, little wind or road noise intrudes into the cabin. Both 148bhp and 173bhp diesel engines are smooth and sound far more like petrol engines, most of the time.

Even the lesser engine offers more than enough muscle for most situations. The twin turbos grant a very broad spread of power, making it feel more flexible and potent than the 148bhp figure would suggest. Low VED and impressive claimed MPG figures add further to the overall package, in either case.

Verdict: Mazda 6

The new petrol engine and posher interior, plus even tidier road manners make the Mazda 6 an even better cut-price BMW 3 Series and a far better prospect than the underwhelming Jaguar XE – courtesy of its sharp drive and better quality cabin.

Throw in very good value PCP finance deals and low cash prices and the 6 is a far more interesting alternative to the straight-laced VW Passat and Ford Mondeo.

Yes the petrol engine and auto combo is an acquired taste – as you need to tell the gearbox what to do with your right foot or the paddles rather than waiting for it to suss you out – but tune into how it wants you to drive and it’s a satisfying machine to steer.

Since the twin-turbo diesel engines have always been a strong point for the current Mazda 6, we’d wager that you might want to wait for the upcoming 181bhp diesel. Its immense mid-range muscle, extremely good refinement and the option of a manual gearbox could make this the 6 to go for – even though diesel power has a bad rap right now.